t r u e s d b l l



@niet mit -atwf @new Letters Patent Nin-76,558, dated April 7, 1868.

IMPROVEMENT 'IN BRIDGES.:

dlgs Stigiitlr rifatta tu im tigen tetter 'zzient mit making giri utilgenmr.

TO ALL WHOM IT MAYOONGERN: l Be it known that I, Lf E. TRESDELL, oilChicago, in tho.county of Cook, aud-State of Illinois, have invented anew Aand usefullmp'rovement in Iron Bridges and I do hereby declare thefollowing to be a full and exact description thereof, reference beinghad to the accompanying drawings, and to the letters of'refer'- encemarked thereon, making apart of this 'speciticatiomin which- .Figure 1is side elevationA of my invention.

'Figure 2 is a vertical transverse section through the same.

Figure 3 is a vertical section through one of the posts on line e e,showing the manner of connecting its corresponding parts. I

Figure 4 is a transverse section of one of the postsY on lines w x,sii-owing the manner of cornecting the' bars which form the lowerchord.A i

-Figure 5 is a detached sectionof a. portionv of fthe arch-cap on lineshowingthe manner of holding the outer ends of` the ties. i i

v Figure 6 is a vertical transverse section through the cap on line d d,`showingthe shapethereot.

Similar letters of reference, as theyoccur in the separate figures,denote like partsin both of the drawings. My inventionrelates to animprovement in Athat class of bridges which is' constructed of'iron; andthe nature of my improvement'cousists, Y

First, in the shape of the caps and posts, as will be hereinafter morefully explained. Second, in the manner'of` connecting the several partsone to the other, whereby great 'strength and durability are obtained ata much less expense'than any oi' the heretofore-known arrangements.

To enable others skilled in the art to more fully understand andconstruct my invention, I will proceed to describe the same lwithreference to the drawings. i

`A and A represent the caps or upper beam Iof the bridge. The latter isconstructed in a circular form laterally, and provided with projectionsor iianges extending upward and` downward from the centre-whereby greatstrength is obtained. The former cap, A, is constructed in a likeruann'er, laterally,'and slightly curved, or arched longitudinally, andis hingedor jointed. at the lower end'to clamp-plates D D,that-'holdvthe outer v ends of the bars which form the lower chords Cand C. Said caps extend obliquely upward, and pass into mortises cut inand -through the upper ends of posts B B,and are there connected to capsA by means of a look or dove-tail joint, as shown in the drawings byig.3. Said posts extend downward to a. distance suiiieient to bring thelower` ends thereoi` in a horizontal line with the lower end oi'clamp-plates D D,.and are provided with slots cut therein,inthedirection ofthe length of the bridge,l for-the reception of chords C andC, the parts of said posts protruding downward. l. Each side of saidslots' is iuted, or provided with a seres'of vertical corrugations,which correspond with and take into'a like series of corrugations in theend of the bars which form chords C and C, as the ends of the sameareiapped or placed together within said slots, and are held thereinbymeans of key z', passing through moi-tiefes cutin said post sat rightangles with said slots, said key coming in contact with and against unadjustable slide, E, forcing the same upward againstsaid bars, thusfirmly connecting the same the entire length oi' the bridge.

The lower side of caps A and A. is provided 'at the'joint thereof', andwithin the mortises in said posts, with a series of corrugations, cuttherein transversely, which receives the ends of ties S and S. The endsthereof are slightly curved, and also corrugated, corresponding one withthe other, and are held together and within the corrugations in saidcaps by means of slide E passing through the mcrtisc in said post underthe' ties. i Suid slide is also corrugated, agreeing with thecorrugations in said ties, and is capable of vertical adjustment bymeans oi` hey t' passing through al mortise lcutthrough said posts atright angles with and under said slide, thus forcing the same upward,which firmly connects the several parts one to the other.

Ties S'and S extend obiiquely downward, and are'connected to the lowerend of the posts in a like manner as shown by fig. 3. That portion oftheposts between the slotsvis also corrugated, which. receivesthecorrugated part doi' the ties, and is held together by meansot'slide. E, which is also tinted, and forced upward by ke)7 2'. Thusthe entire structure is iirmiy connected together; The ends ofthe outertiesl S S are held vithin u, bevelled corrugated clmp-plate, H H, whichi hield withina-corresponding mortis@` cnt through tho :entre of capVA,` as shown byifig. 5. i

Thesides of the bridge are connected laterally by means of sillsPpassing across from post to post, as ihown by fig. 2. The Hoor F issupported by menne of joist T resting upon chords C amalfi/lf Posts B Bnre constructed with four {langes,'a.s shown at L, fig. 3, and siightlytapered f'iourthe centre upward and downward, nearly to that portion ofpost through which the mortises are out, and are there'enlarged io girethe necessary strength,`

l ,The obj-ct of this style of pestis to give greater strength with lessheft of iron,l :is the angcs :1ct as a..

)race one for the other.

Hoving thus described the lnature and object of my invention, what Iclaim as new, :md desire to secure )y Letters Patent, s

` l. The construction and arrangement of the corrugated clamp-plates H,in combination with the itie-rods S, in the manner and for'the purposeherein described. I

2. The construction `und arrangement ofi-the caps A and Af and posts Bof a bridge s o that the suspension- 'ods may beV clampedA together b'ymeans of the corrugations upon the ends of the same, and held {rmlyviuposi- :ion by means of clamp E andwedge or'key z', substantiallyin themanner ,and for the purpose herein described. L. E. TRUESDELL.

Witnesseszf N. H. SHEnBUBNE, .JAMES COLEMAN.

